mysql> SELECT YEAR(birthday) AS year,
    -> REPEAT('*', COUNT(*) / 10) AS user_count
    -> FROM user
    -> WHERE userid >= 0 AND userid <= 100000 AND birthday > '1900-01-01'
    -> GROUP BY YEAR(birthday)
    -> HAVING LENGTH(user_count) > 0;
+------+----------------------------------------------------------+
| year | user_count                                               |
+------+----------------------------------------------------------+
| 1938 | *                                                        |
| 1939 | *                                                        |
| 1940 | *                                                        |
| 1941 | *                                                        |
| 1942 | **                                                       |
| 1943 | *                                                        |
| 1944 | **                                                       |
| 1945 | ***                                                      |
| 1946 | ***                                                      |
| 1947 | ****                                                     |
| 1948 | ***                                                      |
| 1949 | ****                                                     |
| 1950 | *****                                                    |
| 1951 | *****                                                    |
| 1952 | ****                                                     |
| 1953 | ******                                                   |
| 1954 | ******                                                   |
| 1955 | ********                                                 |
| 1956 | ********                                                 |
| 1957 | *********                                                |
| 1958 | ********                                                 |
| 1959 | ********                                                 |
| 1960 | **************                                           |
| 1961 | ***********                                              |
| 1962 | ************                                             |
| 1963 | ***************                                          |
| 1964 | *************                                            |
| 1965 | *****************                                        |
| 1966 | *******************                                      |
| 1967 | *******************                                      |
| 1968 | ********************                                     |
| 1969 | **********************                                   |
| 1970 | ****************************                             |
| 1971 | ***************************                              |
| 1972 | *************************                                |
| 1973 | ***************************                              |
| 1974 | *******************************                          |
| 1975 | *********************************                        |
| 1976 | *******************************                          |
| 1977 | ************************************                     |
| 1978 | *************************************                    |
| 1979 | ************************************                     |
| 1980 | ******************************************************** |
| 1981 | *****************************************                |
| 1982 | ***********************************************          |
| 1983 | **************************************************       |
| 1984 | **********************************************           |
| 1985 | *****************************************************    |
| 1986 | *******************************************************  |
| 1987 | ********************************************             |
| 1988 | ***********************************************          |
| 1989 | **********************************                       |
| 1990 | *****************************                            |
| 1991 | ***********                                              |
| 1992 | *****                                                    |
| 1993 | **                                                       |
+------+----------------------------------------------------------+
56 rows in set (0.14 sec)